ID   HMT1_MAIZE              Reviewed;         323 AA.
AC   Q9FUN0;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2001, sequence version 1.
DT   03-AUG-2022, entry version 98.
DE   RecName: Full=Homocysteine S-methyltransferase 1;
DE            EC=2.1.1.10;
DE   AltName: Full=S-methylmethionine:homocysteine methyltransferase 1;
DE            Short=SMM:Hcy S-methyltransferase 1;
DE   AltName: Full=ZmHMT-1;
GN   Name=HMT-1;
OS   Zea mays (Maize).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; Liliopsida; Poales; Poaceae; PACMAD clade;
OC   Panicoideae; Andropogonodae; Andropogoneae; Tripsacinae; Zea.
OX   NCBI_TaxID=4577;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=11309147; DOI=10.1046/j.1365-313x.2001.00988.x;
RA   Ranocha P., McNeil S.D., Ziemak M.J., Li C., Tarczynski M.C., Hanson A.D.;
RT   "The S-methylmethionine cycle in angiosperms: ubiquity, antiquity and
RT   activity.";
RL   Plant J. 25:575-584(2001).
CC   -!- FUNCTION: Catalyzes methyl transfer from S-methylmethionine (SMM) to
CC       adenosyl-L-homocysteine (AdoMet). SMM degradation (by HMT-1, HMT-2,
CC       HMT-3 and HMT-4) and biosynthesis (by MMT1) constitute the SMM cycle in
CC       plants, which is probably required to achieve short term control of
CC       AdoMet level (By similarity). {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-homocysteine + S-methyl-L-methionine = H(+) + 2 L-
CC         methionine; Xref=Rhea:RHEA:26337, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:57844, ChEBI:CHEBI:58199, ChEBI:CHEBI:58252; EC=2.1.1.10;
CC   -!- COFACTOR:
CC       Name=Zn(2+); Xref=ChEBI:CHEBI:29105;
CC         Evidence={ECO:0000255|PROSITE-ProRule:PRU00333};
CC   -!- SUBUNIT: Monomer. {ECO:0000250}.
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DR   EMBL; AF297044; AAG22537.1; -; mRNA.
DR   RefSeq; NP_001105011.1; NM_001111541.1.
DR   AlphaFoldDB; Q9FUN0; -.
DR   SMR; Q9FUN0; -.
DR   STRING; 4577.GRMZM6G310687_P02; -.
DR   PaxDb; Q9FUN0; -.
DR   PRIDE; Q9FUN0; -.
DR   EnsemblPlants; Zm00001eb399940_T001; Zm00001eb399940_P001; Zm00001eb399940.
DR   GeneID; 541873; -.
DR   Gramene; Zm00001eb399940_T001; Zm00001eb399940_P001; Zm00001eb399940.
DR   KEGG; zma:541873; -.
DR   eggNOG; KOG1579; Eukaryota.
DR   HOGENOM; CLU_004914_3_2_1; -.
DR   OMA; HRPRMKA; -.
DR   OrthoDB; 731388at2759; -.
DR   Proteomes; UP000007305; Chromosome 9.
DR   ExpressionAtlas; Q9FUN0; baseline and differential.
DR   Genevisible; Q9FUN0; ZM.
DR   GO; GO:0047150; F:betaine-homocysteine S-methyltransferase activity; IEA:InterPro.
DR   GO; GO:0008898; F:S-adenosylmethionine-homocysteine S-methyltransferase activity; IEA:EnsemblPlants.
DR   GO; GO:0061627; F:S-methylmethionine-homocysteine S-methyltransferase activity; IEA:RHEA.
DR   GO; GO:0008270; F:zinc ion binding; IEA:InterPro.
DR   GO; GO:0009086; P:methionine biosynthetic process; IEA:UniProtKB-KW.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   Gene3D; 3.20.20.330; -; 1.
DR   InterPro; IPR017226; Betaine-hCys_S-MeTrfase_BHMT.
DR   InterPro; IPR003726; HCY_dom.
DR   InterPro; IPR036589; HCY_dom_sf.
DR   Pfam; PF02574; S-methyl_trans; 1.
DR   PIRSF; PIRSF037505; Betaine_HMT; 1.
DR   SUPFAM; SSF82282; SSF82282; 1.
DR   PROSITE; PS50970; HCY; 1.
PE   2: Evidence at transcript level;
KW   Amino-acid biosynthesis; Metal-binding; Methionine biosynthesis;
KW   Methyltransferase; Reference proteome; S-adenosyl-L-methionine;
KW   Transferase; Zinc.
FT   CHAIN           1..323
FT                   /note="Homocysteine S-methyltransferase 1"
FT                   /id="PRO_0000114614"
FT   DOMAIN          3..317
FT                   /note="Hcy-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
FT   BINDING         235
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
FT   BINDING         302
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
FT   BINDING         303
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
SQ   SEQUENCE   323 AA;  34927 MW;  1B1B8F19DA0B743D CRC64;
     MGVLEDLVAR AGGCAVIDGG FATQLEALGA DINDPLWSAA CLITRPHLVK EVHMQYLEAG
     ADVIISSSYQ ATIPGFIARG MSVAEAEDLL RTSVKLANEA RDEFWKSTLR KSKPIYNRAL
     VAASIGSYGA YLADGSEYSG SYGADITAEK LKDFHRRRLQ VLASAGPDLI AFEAIPNQME
     AQALVELLEE EKVQIPSWIC FSSVDGKNLC SGESFADCLK ILNASEKVAV VGVNCTPPQF
     IEGIICEFRK QTKKAIAVYP NSGEVWDGRA KRWLPVECLG HKSFDALAKR WQEAGASLIG
     GCCRTTPSTI RAVSKILKGR TGH